The lateral grey column (lateral column, lateral cornu, lateral horn of spinal cord, intermediolateral column) is one of the three

grey column The grey column refers to a somewhat ridge-shaped mass of grey matter in the spinal cord. This presents as three columns: the anterior grey column, the posterior grey column, and the lateral grey column, all of which are visible in cross-section ...

s of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

(which give the shape of a butterfly); the others being the anterior and posterior grey columns. The lateral grey column is primarily involved with activity in the sympathetic division of the autonomic

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power g ...

system. It projects to the side as a triangular field in the

thoracic The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

and upper lumbar regions (specifically T1- L2) of the postero-lateral part of the

anterior grey column The anterior grey column (also called the anterior cornu, anterior horn of spinal cord, motor horn or ventral horn) is the front column of grey matter in the spinal cord. It is one of the three grey columns. The anterior grey column contains motor ...

Background information

Nervous system

The

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

is the system of neurons, or nerve cells that relay electrical signals through the brain and body. A nerve cell receives signals from other nerve cells through tree-branch-like extensions called

dendrites Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the ...

and passes signals through a long extension called an

axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...

(or nerve fiber). Synapses are places where one cell's axon passes information to another cell's

dendrite Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the ...

by sending chemicals called

neurotransmitters A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neurot ...

across a small gap called a

synaptic cleft Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous syste ...

. Synapses occur in various locations, including ganglia (singular: ganglion), which are masses of nerve cell bodies. Preganglionic nerve cells in the sympathetic nervous system (all of which come from the lateral grey column), use the neurotransmitter acetylcholine, while postganglionic sympathetic nerve cells use

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad' ...

Grey matter Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distingu ...

in the brain and spinal cord is any accumulation of cell bodies and

neuropil Neuropil (or "neuropile") is any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies. The most prevalent an ...

(neuropil is tissue rich in nerve cell bodies and dendrites).

White matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distributi ...

consists of nerve tracts (groups of axons) and

commissures A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commi ...

(tracts that cross the brain's midline).

Sympathetic nervous system

The

is divided into the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

(brain and spinal cord) and the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain ...

(everything else). The peripheral nervous system is divided into the

somatic nervous system The somatic nervous system (SNS), or voluntary nervous system is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The somatic nervous system consists of sensory nerves carr ...

(voluntary processes) and the autonomic nervous system (involuntary processes). The autonomic nervous system is divided into the parasympathetic nervous system (normal functioning) and the sympathetic nervous system (emergency functioning). The lateral grey column mediates the functions of the sympathetic nervous system.

Spinal cord

The

is divided into 31 segments, located between the

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

. Each segment is defined by a posterior root entering it and an anterior root exiting it. Each of these roots is the end of a spinal nerve connecting the spinal cord to the body. The

vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordate ...

is divided into four groups of vertebrae: (from top to bottom)

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cerv ...

, lumbar, and

sacral Sacral may refer to: *Sacred Sacred describes something that is dedicated or set apart for the service or worship of a deity; is considered worthy of spiritual respect or devotion; or inspires awe or reverence among believers. The property ...

.Dafny, N. (1997). Anatomy of the spinal cord. http://neuroscience.uth.tmc.edu/s2/chapter03.html

Structure

The lateral grey column is present at 17 levels of the spinal cord, specifically through levels T1-L2 (sympathetic outflow) as well as through levels S2-S4 (parasympathetic outflow).Dlugos, C. (1999). ''Autonomic nervous system.'' http://www.smbs.buffalo.edu/ana/newpage41.htm Both these segments are located within the first thoracic vertebra to the first or second lumbar vertebra as the spinal cord ends here and the nerves form the

cauda equina The cauda equina () is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlarg ...

Sympathetic Circuit from the Lateral Horn

The lateral grey column is composed of sympathetic preganglionic visceral motor neurons which are part of the autonomic nervous system. An in-depth study of the lateral grey columns in the thoracic region of rats revealed two types of cells. One cell type was characterized by many mitochondria, an indented

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

, and a long endoplasmic reticulum, while the other cell type had an increased cytoplasmic density and a short endoplasmic reticulum. Lateral column

axon terminals An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...

were found to contain

noradrenaline Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...

storage granules and could be divided into four types. Type one terminals contained a few large and many small granular

vesicles Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle ; In human embryology * Vesicle (embryology), bulge-like features o ...

, and type two terminals had many large vesicles and barely noticeable granules. Type three terminals contained small, spherical vesicles and no granules, and type four were the rarest terminals that had flattened vesicles with small and large granules. The cells of the intermediolateral cell column are fusiform or star-shaped, and of a medium size. The

intermediolateral cell column The intermediolateral nucleus (IML) is a region of grey matter found in one of the three grey columns of the spinal cord, the lateral grey column. This is Rexed lamina VII. The intermediolateral cell column exists at vertebral levels T1 – L ...

exists at vertebral levels T1 - L2 and mediates the entire sympathetic innervation of the body. In the upper part of the cervical region and lower part of the medulla oblongata, as well as in the third and fourth sacral vertebrae, this column is again differentiated.

Functions

The lateral grey column's connections mediate the functions of the sympathetic nervous system (SNS), which changes cardiac, pulmonary, hepatic (liver), and gastrointestinal activities to prepare the body for emergency situations (although the sympathetic system is always active to some extent, including in the absence of a stressful environment, to maintain the appropriate level of sympathetic function). When the brain responds to potential threats by sending signals to lateral grey column cells, the lateral column passes on the signals to initiate a variety of physiological changes that prepare the body for a “

fight-or-flight The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...

” response. Hairs stand up to conserve heat. The gut relaxes and

digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...

slows so that more energy can be directed toward dealing with the threatening situation. The adrenal medulla is activated and releases epinephrine (adrenaline) into the bloodstream, where it mediates many changes, such as the preparation of muscles for emergency activity. A variety of smooth muscles relax; for example, the muscles wrapped around the bronchioles of the lungs relax, allowing more

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

to enter the bloodstream.

Heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

increases to ensure all cells are supplied quickly with the substances they need. The

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

produces

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

(sugar) to fuel the muscles. Blood vessels contract (

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vess ...

), which reduces bleeding and conserves body heat (the exception is blood vessels fueling large muscles that would be used in running or fighting). The pupils dilate, improving vision.

Perspiration Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...

increases in certain areas of the body (the purpose of this is not yet fully understood, but there is some evidence that the odor produced by this sweat serves as a signal to other individuals).

Sympathetic

The lateral grey column plays an important role in the sympathetic division of the visceral (autonomic) motor system. Neuron cell bodies in the lateral column send their axons to synapse on sympathetic ganglia that innervate autonomic and pelvic organs; in fact, all preganglionic neurons in the sympathetic nervous system originate in the lateral grey column. Neurons in the upper and middle thoracic segments control sympathetic activity in organs in the head and thorax, while neurons in the lower thoracic and upper lumbar segments control abdominal and pelvic organs and targets in the lower extremities. Slightly myelinated preganglionic fibers (aka visceral efferent fibers) leave the lateral grey column through the ventral roots and promptly form fourteen aggregates called white rami communicantes, also known as white communicating rami, which eventually enter the

sympathetic trunk The sympathetic trunks (sympathetic chain, gangliated cord) are a paired bundle of nerve fibers that run from the base of the skull to the coccyx. They are a major component of the sympathetic nervous system. Structure The sympathetic trunk lies j ...

, a structure next to the

that consists of paired chains of sympathetic ganglia connected by nerve fibers. Most often, the fibers from the lateral grey column will travel along the sympathetic trunk until they synapse on one of the trunk's ganglia, which then passes on the information via

postganglionic fibers In the autonomic nervous system, fibers from the ganglion to the effector organ are called postganglionic fibers. Neurotransmitters The neurotransmitters of postganglionic fibers differ: * In the parasympathetic division, neurons are ''cho ...

in a

gray ramus communicans Each spinal nerve receives a branch called a gray ramus communicans (plural rami communicantes) from the adjacent paravertebral ganglion of the sympathetic trunk. The gray rami communicantes contain postganglionic nerve fibers of the sympathetic ne ...

. 31 pairs of gray rami communicantes exit the sympathetic trunk to join the 31 pairs of

spinal nerves A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the ...

and travel to targets such as

sweat glands Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...

, hair follicles, and blood vessels. Some fibers, such as the ones that innervate the heart, join the spinal nerves directly, without first joining a gray ramus communicans. Other fibers from lateral grey column neurons pass through the sympathetic trunk without synapsing there. The greater

splanchnic nerve The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system ( visceral efferent fibers) as well as sensory fibers from the organs ( visceral a ...

leaves the vertebral levels T5-T9 and synapses in the abdomen in the

celiac ganglia The celiac ganglia or coeliac ganglia are two large irregularly shaped masses of nerve tissue in the upper abdomen. Part of the sympathetic subdivision of the autonomic nervous system (ANS), the two celiac ganglia are the largest ganglia in t ...

, which innervates the

celiac artery The celiac () artery (also spelled ''coeliac''), also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12) in ...

(splanchnic nerves are the nerves that innervate thoracic and abdominal viscera). The lesser splanchnic nerve travels from the vertebral levels T10-T11 to the abdomen's

superior mesenteric ganglia The superior mesenteric ganglion is a ganglion in the upper part of the superior mesenteric plexus. It lies close to the origin of the superior mesenteric artery. Structure The superior mesenteric ganglion is the synapsing point for one of the ...

, which innervates the

superior mesenteric artery In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the du ...

, and to the aorticorenal ganglion. The least, or lowest, splanchnic nerve connects the T12 level to the

renal plexus The renal plexus is a complex network of nerves formed by filaments from the celiac ganglia and plexus, aorticorenal ganglia, lower thoracic splanchnic nerves and first lumbar splanchnic nerve and aortic plexus. The nerves from these sources ...

. The

lumbar splanchnic nerves The lumbar splanchnic nerves are splanchnic nerves that arise from the lumbar part of the sympathetic trunk and travel to an adjacent plexus near the aorta. They originate from L1 and L2. These nerves contain preganglionic sympathetic and gener ...

from the upper two lumbar segments synapse in the abdomen on the inferior mesenteric ganglia, associated with the inferior mesenteric artery. In addition, some thoracic fibers in the splanchnic nerves innervate the adrenal medulla, a ganglion in the abdomen that mediates the sympathetic response to stress. Axons from the lateral grey column release acetylcholine at their synapses. This can excite or inhibit the postsynaptic cell, depending on the type of acetylcholine receptor in its membrane. Postganglionic cells (that is, nerve cells innervated in ganglia by lateral column neurons) typically release

(noradrenaline) on their targets; these synapses can also be either excitatory or inhibitory. The lateral grey column receives input signals from preganglionic, myelinated fibers from

viscera In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...

(internal organs), which course through

prevertebral ganglia Prevertebral ganglia (or collateral ganglia, or preaortic ganglia) lie between the sympathetic ganglia and the target organ. Function Similar to the paravertebral ganglia, the prevertebral ganglia are the nodules where preganglionic neurons sy ...

(between the visceral organ and the sympathetic chain) and

paravertebral ganglia The sympathetic ganglia, or paravertebral ganglia are autonomic ganglia, of the sympathetic nervous system. Ganglia are 20,000 to 30,000 afferent and efferent nerve cell bodies that run along on either side of the spinal cord. Afferent nerve c ...

(in the sympathetic chain), white rami communicantes, and dorsal roots to synapse on cells of the intermediolateral cell column in the lateral horn. Lateral grey column nerve cells also receive signals from the brainstem and from neurons in the

hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...

, a brain area involved in mediating many physiological functions and emotional states.Harting, John. "Hypothalamus," ''Neuroscience Coursebook''. University of Wisconsin. January 21, 2005. Web. http://www.neuroanatomy.wisc.edu/coursebook/neuro2(2).pdf

Clinical significance

Horner's syndrome Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...

is characterized by small pupils, sunken eyes, partially drooping eyelid, and dryness of the skin on the face. It is caused by problems in autonomic pathways such as damage to the lateral grey column. Progressive autonomic failure is a disease associated with autonomic disturbances due to selective neuronal degeneration. A study estimated the number of nerve cells in the lateral grey columns of 21 people with progressive autonomic failure in comparison with a control group. This same study found that an average of 75 percent of the lateral column cells were lost in people with progressive autonomic failure. Multiple system atrophy (MSA) is an adult onset disorder that is a sporadic and progressive. MSA is characterized by a combination of

ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...

parkinsonism Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia (slowed movements), rigidity, and postural instability. These are the four motor symptoms found in Parkinson's disease (PD), after which it is named, dementia with Lewy b ...

, and

autonomic dysfunction Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has ...

. A study did a comparison with the lateral grey column nerve cell count between 15 cases of patients with MSA and a control group. All cases of MSA had lost over 50 percent of their lateral horn cells which shows the involvement of the intermediolateral columns in MSA. Lichtheim's disease (also known as subacute combined degeneration) is the result of a

vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. ...

deficiency and is associated with

pernicious anemia Pernicious anemia is a type of vitamin B12 deficiency anemia, a disease in which not enough red blood cells are produced due to the malabsorption of vitamin B12. Malabsorption in pernicious anemia results from the lack or loss of intrinsic fa ...

. The disease is characterized by the degeneration of both the lateral and posterior columns, which results in symptoms such as a spastic ataxic gait and paranoia.Benzel, E., Waxman, C., Stephen, G., Byrne, T. N. "Diseases of the Spine and Spinal Cord." Oxford University Press, USA, 2000. Patients may also feel tingling or weakness in their limbs and torso.

References

{{Authority control Spinal cord